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// Other services

Port 4022: DNOX

Port 4022 is assigned by IANA to dnox (DNOX).

4022

How dnox works

Other services
client:4022dnoxresponse client:4022dnoxresponse

The client sends a request to port 4022 and the dnox service answers.

Transport
TCP · UDP
Exposure risk
not rated depends on the program listening
Encryption
Unknownnot stated by the registry
IANA status
Assigned1 registered service
Range
Registered (1024-49151)
Category
Other services
01 Security

Is port 4022 dangerous?

We have no specific security note for port 4022. Its risk depends on the program actually listening on it. General advice for other services services:

  • Close the port if nothing on the host needs it.
  • Identify the process that listens on it (commands below) before opening it in a firewall.
  • Expose a service only to the networks that use it.
02 Registry

IANA registry entries for port 4022

ServicePortTransportDescriptionReferenceUpdated
dnox 4022 TCP, UDP DNOX - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 4022, and is it reachable?

Linux

sudo ss -ltnup 'sport = :4022'      # process listening on 4022
sudo lsof -nP -i :4022

macOS

sudo lsof -nP -i :4022

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 4022 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 4022
netstat -ano | findstr :4022

From another machine

nmap -p 4022 -sV <host>
sudo nmap -sU -p 4022 <host>
nc -zv <host> 4022

Block it in the firewall

sudo ufw deny 4022/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 4022" -Direction Inbound -LocalPort 4022 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 4022 used for?

Port 4022 is assigned by IANA to dnox (DNOX).

Is port 4022 TCP or UDP?

Port 4022 is registered for TCP and UDP.

Is it safe to open port 4022?

It depends on the program that listens on it. Open it only for a service you know and only to the networks that need it. Close the port if nothing on the host needs it.

How do I check if port 4022 is open?

On Linux run "ss -ltnup 'sport = :4022'", on macOS "lsof -nP -i :4022", and on Windows "netstat -ano | findstr :4022" to see the local process. From another machine, "nmap -p 4022 <host>" shows whether it is reachable.

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